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blizzard81

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Posts posted by blizzard81

    Model Output Discussion 1200 hrs 15/11/14

    in Forecast Model Discussion

    Posted · Edited by blizzard81

    I think model fatigue has set in a little earlier this season, hence the lack of posts. I am wondering what the ECM will throw up tonight. It's interesting that 2 or 3 days ago the ECM 12z threw out a very high pressure dominated run in it's later stages and this seems to be what the GFS and UKMO are picking up on now.

    Stratosphere Temperature Watch 2014/2015

    in Spring Weather Discussion

    Posted

    Thanks Matt, I'm sure that for most people the back end of December would be the perfect time for some wintry synoptics!

     

    Apologies if this has been covered elsewhere but I'm puzzled by the disparity we see between all the promising signs and signals and the forcasts of the seasonal models. Surely the current state of the vortex and on going wave 1, 2 (and possibly 3) activity must be factored in? Is it just that the models don't see a tropospheric response from this activity or perhaps a they show a response which just doesn't impact (in terms of cold weather) on our small part of the world?

    I wonder the same thing. What do the seasonal models base their long term forecasts on ? All I see are anomaly maps for pressure and temps but no explanation as to how they reach their conclusions. Does anyone know ?

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    I just feel that the majority on here are interpreting this so wrongly (and very recent events support this). With a lobe of the PV over N.America bringing cold weather there this is the ideal set up for a conveyor of low systems to develop over NW Atlantic and head for the NE Atlantic where the temperature differential across the N.Atlantic is accelerating the Jet Stream and this will deepen any lows. Something the models proved last December / January that they cannot see very well. There is a slight blocking pattern; but this will be overwhelmed by the low altitude effect of the heat of the N.Atlantic (where SST are anomalously 5C higher than average over Nova Scotia) driving the creation of low pressure systems under the anomalously low temps at high altitude. Its stormy weather not snowy!

    This is what the models were showing up until a couple of days ago but they have backtracked somewhat and the block to our east

    is much more resilient than they were originally forecasting. This is why the stormy atlantic is not a feature so much now in the forecasts.

    • Like 2

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    Just 24hrs ago the ECM ens mean was showing this for the 24th.

     

    EDM1-240_fti5.GIF

    Now    EDM1-216_lrj6.GIF      

     

    Unusual for the ECM ens to swing so much so quickly.. so the models are clearly in a mess at the moment.

     

    A lot of uncertainty with the situation to our W/NW... LP dominance vs HP dominance? NAEFS spreads

     

    naefsnh-6-0-252_vsx7.png

    That's a great post and ties in with what Fergie said yesterday with regards to MOGREPS trending to higher pressure building more,

    especially over the south.

    • Like 2

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    For all those still thinking the Scandi ridge will be more resilient than the models are predicting, well the trend over the last 24hrs says to me that ship has sailed. The ECM has been the main culprit in giving false hope of a more robust block to our north east. I seem to remember that it was guilty of exactly the same thing last winter. I lost count of how many times the ECM showed undercuts and pressure falling over Europe from 192hrs onwards only for it to never verify. I wonder why pressure remains so stubbornly high over Europe during our winters ?

    • Like 5

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    Signs of a change upstream over the east Pacific looking at the models, with the large scale upper pattern that brough the high latitude block fromed from wavenumber 1 breaking down and a more active Pacific jet firing up across the Pacific northwest, this ties in with EPO forecast to go from a -ve phase to a +ve one.

     

    ftp://ftp.cdc.noaa.gov/Public/gbates/reforecast2/teleconn/4panel.png

     

    This has the implication of the cold vortex eventually relaxing its grip over Canada, central and eastern USA. The model operationals and ens seem to gather n the idea of pushin the core of low heights/cold vortex  over E Canada moving out across NW Atlantic and Greenland, which may seem like bad news, but if blocking over northern Europe holds it could amplify a trough over the mid-Atlantic with WAA helping strengthening blocking to the east further, perhaps creating a block over Scandi.This is one possible outcome of the pattern change coming upstream in next 11-15 days ... not to say it will pan out like that.

     

    But wouldn't bank on a prolonged bout of Atlantic lows coming our way.

    The two Nick's in tandem here. GFS p uncannily similar to ECM op tonight - food for thought!

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    Please let the ECM op be on to something here. I wish this for three reasons. Firstly, many of the classic cold spells are preceded by a period of blocked, anticyclonic weather. Secondly, the blocked scenario that the ECM is showing allows the cold to build and build to our east and north east. And last but not least, it goes against the Meto extended forecast for the next 2 to 3 weeks. If the met have got the signal wrong for the next couple of weeks then how can their winter thoughts be on the money? :)

    • Like 7

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    Both the gfs ans gfs parallel have picked up on a shortwave running across the south of greenland on this run!! If that's there tomorrow you can say goodbye to a good split for now!! Gfs is amazing at picking up these shortwaves so doubt its wrong! !

    Yeah, see steve murr's post on previous page - post 1103. ECM 12z first to pick up this shortwave. Uncanny how they seem to pop up out of nowhere at just the wrong time!

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    At T240hrs the ECM wants to start off on another journey to build pressure near Greenland. With so much energy digging south into the Atlantic and still a good looking NH set up it still looks like a slow burner. Hopefully someone doesn't extinguish the flame before its delivered something. I do get the feeling this is like one of those very long films with a lot of plot twists, hopefully we end up with the sledges and earmuffs ending rather than the, is that it let down!

    That's a fantastic way to explain the ECM tonight Nick. I find the wording in your posts very entertaining. I agree, the ECM looks messy post 144hrs.

    • Like 3

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    definately mate!!am sort of surprised to see the nao and ao that negative aswell!!its a better update than yesterday's!!I think come this evening if we don't progress from last night's 12zs regarding heights around greenland and the pattern backing west then that will probably be that for any chances of getting cold into the uk before december!!just my opinion but I could be wrong!!

    I totally agree. What I have noticed about the best cold spells in recent years is once the models pick up major blocking

    patterns - much like the ECM at present, they tend to increase in intensity with each run. That's when I know something interesting

    is around the corner and that is what I am looking for over the next couple of days - cmon winter 14/15  :clapping:

    • Like 1

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    After the last two ECM runs, I have noticed the control turns unsettled and not particularly cold. Trying to piece it all together, it looks as though there will be a cool easterly in a weeks time. We then see a push of very cold air in the Svalbard area push south into northern Scandinavia. This push doesn't make it to our shores as low pressure in the atlantic wins the race and brings in more unsettled weather. Great building blocks though in terms of very cold air building to our north east.

    Just to add to my post - the 06z GFS Parallel shows exactly what I have explained above.

    • Like 1

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    After the last two ECM runs, I have noticed the control turns unsettled and not particularly cold. Trying to piece it all together, it looks as though there will be a cool easterly in a weeks time. We then see a push of very cold air in the Svalbard area push south into northern Scandinavia. This push doesn't make it to our shores as low pressure in the atlantic wins the race and brings in more unsettled weather. Great building blocks though in terms of very cold air building to our north east.

    • Like 2

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    Indeed, is the ECM having another moment ? We will know by the end of tomorrow.

    If this resembles the Dec 2012 ECM fiasco, we really do need to re evaluate our opinion

    of the ECM and it's accuracy post 6 days. I know one thing for sure - the ECM was not prone

    to wild swings so much pre 2012. The wild swings were confined to the GFS. Has ECM caught

    the disease over the last couple of years ? Or is it going to prove it's position as the best ranked model

    over the next couple of days ? These are the questions  :cc_confused:

    Model Output Discussion - 31/10/2014 and Beyond

    in Forecast Model Discussion

    Posted

    Yep was thinking the same.

    If the ECM op has the Atlantic ridging into Greenland modelled correctly at T168hrs, which derails the Atlantic train, then we can see why it almost seamlessly tips the scales towards the colder pattern. 

    http://www.meteociel.fr/modeles/ecmwf/runs/2014110812/ECH1-168.GIF?08-0

     

    again a step further than the other models at mid-range with those heights.

     

    Quite possible of course in view of the 2 wave activity but i think we would all be more confident with support form other runs although even they showed a little more strength in that Greenland ridging but not to the ECM extent that cuts off the Atlantic trough.

     

    Let see if the ECM mean does indeed tilt in that direction later but wrt the overall trend reasons to be cheerful as Ian Drury  once sang. 

    Absolutely, we need to see the other major players jumping on board over the next day or two.

    Looking at tonight's 12z GFS parallel and you may be forgiven for thinking that support has already started to some degree.

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